| Business | Phone |
| Colusa County Assessor 547 Market St, Colusa 95932 | (530) 458-0450 |
| Colusa County Auditor 546 Jay St, Colusa 95932 | (530) 458-0400 |
| Colusa County Controller 547 Market St # 110, Colusa 95932 | (530) 458-0400 |
| Colusa County Tax Collector 547 Market St # 111, Colusa 95932 | (530) 458-0440 |